medwireNews: Left atrial appendage occlusion (LAAO) reduces the risk for ischemic stroke in patients with nonvalvular atrial fibrillation (AF) who have had a prior thromboembolic event despite taking oral anticoagulant therapy (OAT), compared with continuation of OAT alone, shows a study published in JAMA Neurology.
The risk for recurrent stroke in these patients is high, note the researchers, and although the mechanisms vary, “the majority is suggested to be due to cardioembolism; therefore, consensus statement documents suggest LAAO may be a valuable strategy.”
The investigators enrolled 433 patients with nonvalvular AF (mean age 72 years, 61% men) from the international 21-site collaboration STR-OAT LAAO cohort between 2010 and 2022. The participants had undergone LAAO following an ischemic stroke (61%), transient ischemic attack (TIA; 17%), systemic embolism (4%), or an LAA thrombus (18%), despite taking OAT, and had at least 3 months of follow-up. Their mean CHA2DS2-VASc score was 5 points, indicating a high risk for stroke.
These patients were propensity score matched to 433 patients with nonvalvular AF from a collaboration of prospective studies who experienced an ischemic stroke (92%) or TIA (8%) while taking OAT and continued to take it afterwards or switched to another OAT. They were also followed up for at least 3 months.
Lucas Boersma (St Antonius Hospital, Nieuwegein, the Netherlands) and colleagues report that during 2 years of follow-up, there were 16 schemic strokes among patients in the LAAO cohort, compared with 34 among those in the OAT-only cohort, giving a significantly lower annualized event rate of 2.8% versus 8.9%. After adjusting for sex, age, hypertension, diabetes, and CHA2DS2-VASc score, LAAO was associated with a significant 67% lower risk for ischemic stroke than continued treatment with OAT alone.
Additionally, patients undergoing LAAO were a significant 53% less likely to have an ischemic stroke or die from any cause than those receiving OAT, and there were only two incidents of intracranial hemorrhage in the former group versus seven in the latter, a significant difference.
Most (88%) patients underwent LAAO as a stand-alone treatment, while it was combined with other percutaneous interventions, including catheter ablation, in 12%. The periprocedural complication rate was low, at 7.0%, with the most common being pericardial effusion and access site complications, each affecting 2.5% of patients.
There were two deaths after LAAO, from cardiac perforation and a fatal intracerebral hemorrhage. Complete LAA closure was achieved in 74% of patients and minimal and significant peridevice leakage occurred in 22% and 3% of patients, respectively, neither of which affected ischemic stroke risk.
The researchers note that more patients in the LAAO cohort had adequate anticoagulation prior to the index event (92%) than those in the OAT-only group (57%). However, sensitivity analyses including only patients who received adequate anticoagulation showed a comparable stroke risk reduction with LAAO over OAT to that seen in the primary findings.
OAT was discontinued in 290 patients after LAAO, while the remaining 143 continued OAT as an adjunctive therapy to optimize thromboembolic protection. And although LAAO in combination with OAT showed numerically lower event rates compared with LAAO alone in a sub-analysis, this difference was not statistically significant.
Boersma and team observe that while “only technically successful LAAO cases were considered in the STR-OAT LAAO cohort, possibly slightly inflating the impact of LAAO,” the procedure has a “high technical success rate to date (98–99%) and major differences in the treatment effect of LAAO are not anticipated.” They add that technical advances and newer devices are improving the safety of the procedure, which could further augment the positive outcomes associated with LAAO.
The investigators acknowledge that assessing the adequacy of OAT is “extremely difficult,” and therefore advise caution when interpreting the differences between the two cohorts, particularly given the changes in antithrombotic treatment during follow-up in both groups and the use of catheter ablation in 11% of patients undergoing LAAO.
However, they conclude: “These results appear to offer a new and promising treatment option for this population with a very high risk of stroke.
“Randomized clinical trial data are essential to confirm our findings.”
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